Heat cream and oil very gently in a shallow, heavy pan.
Add garlic and cook for 5 minutes.
Remove pan from heat and stir in anchovies and walnuts.
Return the pan to low heat and stir until anchovies are well blended into the sauce.
Season with black pepper.
Keep the dip warm by pouring it into a fondue or earthenware pot and placing over low heat.
Be careful not to let the sauce boil.